Smart microfluidic device with universal coating

ABSTRACT

A medical device comprising a medical device component, the medical device component having an outer surface and an inner surface, a universal coating applied to at least the outer surface or the inner surface of the medical device component, wherein the coating is made from a material selected from the group consisting of diamond, diamond-like, borosilicate glass, carbides and nitrides. The medical device can further be a smart medical device by incorporating a sensor capable of measuring chemical and/or electrical conditions.

FIELD OF INVENTION

This invention relates to “smart” medical devices that are useful for awide variety of patient treatments, as well as methods of manufacturefor these medical devices.

BACKGROUND OF THE INVENTION

Medical devices are used for drug delivery for various substances, suchas morphine, Baclofen, Cisplatin, Clindamycin, Doxorubicin, Floxuridine(FUDR), Methotrexate, Heparin, Mitoxantrone, Octreotide Vinblastine,BDNF (brain derived nerve factor) etc. For example, conventional devicesare specifically used to deliver morphine to cancer patients, baclofento patients experiencing spasticity, and Floxuridine (FUDR) to patientsrequiring chemotherapy (e.g., most of these are treatments alreadyapproved by the FDA).

However, conventional devices have a number of disadvantages. Forexample, conventional devices cannot optically measure theconcentrations of the drug being delivered, nor can they opticallymeasure or monitor the patient site to be treated or being treated toensure that the patient receives the correct amount and concentration ofthe drug to be delivered or being delivered at that site. Conventionaldevices also do not provide for optical detection or an optical triggersignal and/or system to initiate drug delivery. Thus, conventionaldevices are not “smart” devices because they cannot measure biologicalsignals and/or monitor and control the concentration and amount of drugdelivery.

Further, since conventional devices do not monitor the concentration andquality of the delivered drug, they cannot provide this information to amicroprocessor, and thus, the microprocessor cannot analyze or controlthe amount and/or concentration of the drug based on that information.Conventional devices also cannot optically monitor the mixing of varioussubstances that yield mixtures of short shelf life within theseconventional devices, and thus cannot control the mixing of substancesfor optimum concentration of the mixed fluid to be delivered by thedevice to the patient.

Conventional devices can also experience corrosion due to the physicalproperties of substances to be delivered by these devices and thematerials of conventional device components. Many of the drugs have highor low pHs that can cause severe corrosion to the components ofconventional devices.

In addition, conventional devices do not have a coating suitable for awide range of applications and delivery of various drugs (i.e., a“universal” coating), thereby leading to increased surgery to implantdevices suitable for specific drugs or a limitation in the number ofdrugs that could be utilized in such devices.

In addition, conventional devices do not have coatings that can beeasily converted into electrodes for the monitoring of electroactiveanalytes (e.g., organic molecules, dissolved gases, and metal ions) aswell as the sensing of bioelectric events which indicate physiologicalfunction. Most conventional devices with electrodes require theutilization of separate structures with complicated interconnects(feedthroughs) welded or bonded to a substrate via harsh hightemperature processes. Thus, there is a need for simpler fabricationprocedures at lower temperatures for electrodes that allow threedimensional interconnection.

Further, conventional methods of manufacture of medical devices do notprovide for methods of manufacture of devices having coatings useful fora wide variety of applications. For example, conventional methods ofmanufacture of medical devices do not provide for manufacture ofcoatings having optical windows for optical sensors, or selectivelydoped coatings to provide for monitoring of electrochemical conditionsin various locations throughout the device surface, or coatings toprovide corrosion resistance.

While optical sensors have been used in implantable devices to monitoroxygen in hemoglobin, optical sensors have not been used in implantabledevices to monitor and control drug delivery in medical devices.Further, the optical sensors that have been used to monitor oxygen inhemoglobin comprise sapphire windows brazed onto optical sensors. Suchbrazing requires high temperature manual fabrication and is not wellsuited for microfabrication and automated manufacture.

Catheters having optical sensors could be used on a temporary basis tomeasure the amount of certain substances, such as nitrous oxide, inconnection with temporary drug delivery. They have been used asoximeters as described in U.S. Pat. No. 4,750,495. However, conventionalmedical devices which are implantable are not capable of or designed tomeasure a large variety of concentrations or chemical conditions viaoptical and electrochemical sensors, and thus cannot control treatment,such as drug delivery, to a patient.

Thus, there is a great need for medical devices that overcome the abovedeficiencies in conventional medical devices and the methods ofmanufacture thereof.

SUMMARY OF THE INVENTION

A new smart medical device and methods of manufacture thereof have nowbeen discovered that overcomes the deficiencies of conventional devicesand methods of manufacture. The medical device of the present inventioncomprises an outer surface and an inner surface, and a coating on atleast the outer surface or inner surface of the device. Thisconstruction provides a number of benefits. More specifically, in apreferred embodiment, the device has a universal coating that increasesthe corrosion resistance of the device, enabling the use of drugs withdifferent chemistries, and/or enable the device to be a smart devicethat can monitor and control drug delivery and/or electrical stimulationtherapies.

In a further preferred embodiment, the device has a coating that permitstransmittance of signals, such as optical, electrochemical, electricalor thermal signals, to a sensor and/or microprocessor in the device. Ina preferred embodiment, the coating is a diamond or diamond-likecoating. The signals can relate to a wide variety of measurements, suchas the effect of drug delivery to a specific site within a patient, orthe concentration of a drug to be delivered to a patient, or thetemperature at a specific site within a patient, or the electrochemicalor electrical characteristics at a specific site within a patient.

In a preferred embodiment of the device of the invention, a coating isapplied to at least the outer surface or the inner surface of themedical device. In another preferred embodiment, the medical device alsohas at least one optical sensor and a light diode. The light diode canemit light to a substance to be monitored and the optical sensor sensesthe light transmittance through or reflected by the substance beingmeasured.

In another preferred embodiment of the present invention, two lightdiodes can be used to improve detection by reflectance. Depending on thewavelengths one can detect oxygen or other compounds in accordance withthe present invention. The optical sensor can further send informationregarding the sensed light to a microprocessor in the device, which willthen identify the presence and concentration of the substance, and canfurther control the amount of drug delivery by the device based on themeasurement of the substance. The drug delivery by the device can beaccomplished by an electromechanical, electrochemical, solenoid orpiezoelectric pump that pumps the delivered drug from a reservoir andthrough an catheter to a specific site within the patient. The sensorcan be designed to monitor the drug chemistry and concentration prior todelivery to the patient. This is particularly useful to provide acontrolled and intelligent system to mix drugs within the device, whichmay be desirable because of short shelf life of the mixture. The sensorcan also monitor the mixing and send signals to a controller to alterthe mixing, as well as change the amount of drug delivery as desired.

In another preferred embodiment of the present invention, the device canhave boron doped areas on a diamond or diamond like coating that permitsthe transmittance of electrical signals. Such a doped area or coatingcan function like an ECG or EKG electrode that senses electricalpotentials from cell activity. In accordance with the present invention,multiple doped areas can be fabricated in order to determine directionof bioelectric events within a patient. Additional constructions caninclude ion selective electrodes and other chemical/electrochemicalsensors that utilize amperometric or potentiometric methods (see e.g.,U.S. Pat. Nos. 4,647,362, and 4,578,173, which are incorporated hereinby reference).

In another embodiment of the present invention, a coating is appliedover a metallic membrane, such as a piezoelectric membrane or atransducer such as that described in U.S. Pat. No. 5,880,552(incorporated herein by reference), for a chemical or biochemicalsensor. The piezoelectric membrane can act as a sensor to measurepressure, such as blood pressure. The thin piezoelectric membranedeflects with pressure changes and it generates a small electricalsignal that is proportional to the amount of deflection. The amount ofdeflection can in turn be correlated to the pressure (forces) acting onthe piezoelectric membrane. Alternatively, a non piezoelectric materialcan be used as a membrane and the deflection of this material can bemeasured by optical methods (e.g., diode lasers) The above embodimentsare particularly useful for determining when pressure is too highwhereupon the device can reduce or cease drug delivery to the patient.When pressure is too low, the device will detect this as well, andinitiate or increase drug delivery in an appropriate amount and manner.

In another preferred embodiment of the present invention, a coating canbe used as a protective, corrosion resistant coating for a flowrestrictor and/or flow diffuser used in a drug delivery catheter.

The above coatings can be made of any suitable material, includingdiamond and/or diamond-like materials. A diamond material comprisesessentially a 100% pure diamond structure (sometimes referred to as sp3character). A diamond-like material is a diamond material that has someother components that render the material less than essentially 100%pure diamond structure. Typically, a diamond-like structure (sometimesreferred to as a mixture of sp3 and sp2) is one that is about 90% orgreater pure diamond and the remainder another material (or materials),e.g., graphite.

When corrosion resistance and increased protection of the medical devicecomponents are the primary characteristics desired, the coating can bemade of ceramics, oxides, metals and metal alloys, including crystallineand polycrystalline sapphire, silicon carbides, silicon nitrides,borosilicate glass (e.g., Pyrex® by Corning, Inc.), tantalum, niobium,titanium, ruthenium, hafnium, palladium, platinum, iridium, as well astheir metal alloys and oxides.

The above coatings can be applied to the medical devices of the presentinvention in a number of ways. For example, diamond or diamond-likematerial can be grown onto the device by thermal processing methods,physical vapor deposition (PVD), plasma enhanced physical vapordeposition (PEPVD), and chemical vapor deposition (CVD).

Alternatively, diamond or diamond-like material can be deposited ontothe device by PVD, CVD and RF plasma deposition as described in U.S.Pat. Nos. 4,981,717, 4,504,519, 5,605,759, and 5,393,572 (which areincorporated herein by reference).

A preferred method of manufacture of the present invention comprises thefollowing steps: (1) deposit a diamond or diamond-like coating or otheroptically clear film on a p-type silicon wafer; (2) mask desired areason opposite side to diamond film using suitable masking material (orthermally grow SiO₂) to create a pattern for desired optical windows;(3) etch (anisotropically) until reaching the diamond-like coating film(i.e., a natural etch stop process); and (4) strip off the maskingmaterial or thermally grown SiO₂. Each of the above steps can be easilyautomated and used in mass production of medical devices having thedesired coating.

One objective and advantage of the present invention is the utilizationof radio frequency (RF) plasma depositions to manufacture pre-assembleddevice components, e.g., a drug reservoir for the device, thusfacilitating the manufacturing process. Electrochemical sensorsfabricated with the proposed diamond or diamond like coating requiremuch simpler fabrication procedures at lower temperatures and easy threedimensional (“3D”) interconnection.

The medical devices of the present invention provide for new ways tomonitor and deliver drugs with microelectromechanical devices andcomponents. The present invention provides quality control of the drugdelivery not previously attainable. The medical devices of the presentinvention can optically monitor sites within the patient to be treatedor being treated to trigger drug delivery when needed and/or to makesure that the delivered drug is effectively treating the patient. Themedical devices of the present invention can also be used to measurenitrous oxide levels within the patient, and help control blood flow andcardiac function by delivering drugs in relation to the optically orelectrochemically measured nitrous oxide levels.

Objectives of the present invention include a coating for medicaldevices having good corrosion resistance, transparency for opticalsensing, and improved processability, including microfabrication. Such acoating can be considered a “universal” coating due to the wide range ofapplications, corrosion resistance to a wide variety of substances, andthe improved processability of such coatings onto many different medicaldevices for drug monitoring and delivery.

In accordance with the present invention, diamond and/or diamond-likecoatings can be placed within the medical devices of the presentinvention to facilitate the optical measurement of the chemistry andquality of the delivered drug, as well as monitor the mixing ofsubstances that comprise the delivered drug, and thus control thechemistry and quality of the delivered drug with a microprocessor thatreceives information from the sensors. More specifically, opticalsensors can be placed underneath or within the diamond and diamond-likecoatings to optically measure the chemistry and quality of the delivereddrug within the device or outside the device where the drug is deliveredto the patient.

The medical devices of the present invention can be implanted within thepatient. Alternatively, the medical devices of the present invention canbe used during minimally invasive surgery to deliver drugs to thepatient during such surgery.

The medical devices of the present invention have numerous beneficialproperties over conventional devices. The diamond and diamond likecoatings of the present invention have high oxygen overpotential whichmakes the coating unreactive as a cathode in a galvanic couple or makesit a better electrochemical sensor by eliminating the interference ofoxygen reduction on the electrode surface during potentiometricdetection of chemical species, high dielectric constants, very highthermal conductivity, high hardness properties, biocompatiblity, highlubricity (better than Teflon®) and optical clarity, and thus thesecoatings have features and capabilities that are not provided orattainable by conventional devices. The medical device coatings of thepresent invention can handle acids, bases, chlorides, fluorides, andother difficult solutions without significant corrosion.

Further, medical device coatings of the present invention can be appliedat relatively low temperatures, and can be used for preassembledcomponents, thus increasing manufacturing flexibility.

The medical device coatings of the present invention can be used forfluid handling and storage applications. The medical device coatings ofthe present invention allow the use of optical sensors to senseconcentrations in aggressive media or biological media. The medicaldevice coatings of the present invention can also be engineered withflexible and short molecules incorporated in their molecular structurefor use in curved or flexible components, for example, lead conductors.

The medical devices of the present invention can be coated with thediamond-like coatings. It is highly desirable to coat the surface of amicromachined structure at one time with a corrosion resistant coating.

Further, the coatings of the present invention can be doped withsuitable material, such as boron, so that the coating becomes anelectrode, and the coating can be used for electrochemical measurementand to monitor chemicals and their concentrations. For example, theclear diamond and diamond-like coatings of the present invention can beused as an optical window for a visible, infrared or near infraredsensor and these coatings can also be boron doped selectively andutilized as electrochemical sensors.

The above benefits and features of the medical devices and methods ofmanufacture of the present invention will be apparent to those skilledin the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a preferred method for manufacture of a preferredmedical device component of the present invention.

FIG. 2 illustrates a preferred embodiment of the present invention, andmore particularly, a smart medical device having a coating thatfunctions as a protective ionic/corrosion barrier and as anelectrochemical or optical sensor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a preferred embodiment of the present invention,wherein a core 10, is formed, and then coated with a diamond ordiamond-like coating 20, and then a structural support material 30 isapplied to coating 20, and then the core 10 is removed, resulting in amedical device component 40, comprising structural support material 30having a coating 20. As shown in FIG. 1, core 10 is a rectangular shapedmember having a substrate surface 11. Preferably, core 10 is preparedfor coating application. Methods for preparing core 10 for coatingapplication include, but are not limited to, chemical and or mechanicalpolishing chemical etching, ion etching, ion milling, including thedeposition of adhesion promoters, sacrificial films and/or stressrelieving films. The resulting surface finish is substrate surface 11.It may be preferable to select materials so that the bond between thediamond or diamond-like coating 20 to the structural support material 30is greater than the bond between coating 20 to core 10, so that theremoval of core 10 can be made easily and still preserve the bondbetween coating 20 and structural support material 30. Those skilled inthe art will recognize that sufficiently strong bonds between coating 20and structural support material 30 can be achieved based on materialselection and good surface preparation of structural support material 30or coating 20, such as etching, ion milling including the deposition ofadhesion promoters and intermediate films.

Preferably, coating 20 is a diamond or diamond-like coating. Coating 20can be applied to substrate surface 11 by PVD, PEPVD or any otherdeposition method. This process can then be followed by thermalannealing. This method as illustrated in FIG. 1 eliminates the need forbonding diamond to diamond or DLC to DLC, which are very difficultprocesses.

Many sensor windows, such as optical windows, can be fabricated inaccordance with the present invention by the following method. First, adiamond-like coating film is deposited on a p-type silicon wafer.Second, mask the appropriate areas on opposite side (or thermally growsilicon oxide SiO₂) to create a pattern for the desired window orwindows. Third, etch (anisotropically) until reaching diamond-likecoating film (natural etch-stop process). Fourth, strip the masking overthe masked areas. This process lends itself to automatic, massproduction, which reduces fabrication costs.

Another embodiment of the present invention comprises fabrication of adiamond or diamond-like coating without a bonding method. In thisalternative embodiment, the diamond-like coating is applied to thesubstrate using a micromolding process. This process comprisesfabricating a “negative” three dimensional structure substrate out of alow melting point or chemically dissolvable material (e.g., a polymer,low melting point metal, ceramic, or sol-gel), and then depositing afilm of diamond-like coating, silicon coating or other coating tocompletely cover the substrate. Other supporting film material can beincluded in the support if desired. The next step in this process is tocreate at least one opening out of the structure (e.g., using amicrodrill, laser ablade, high pressure water and/or other technique(s))in order to melt or dissolve inside material.

The present invention provides a method of manufacture of a medicaldevice, comprising: (a) fabricating a removable three dimensionalstructure, the removable three dimensional structure made from a lowmelting point or chemically dissolvable material; (b) depositing auniversal coating onto the removable three dimensional structure, theuniversal coating selected from the group consisting of diamond,diamond-like, borosilicate glass (e.g., Pyrex® by Corning, Inc.),carbides, and nitrides; (c) applying a support structure to theuniversal coating; (d) forming an opening in the support structure andthe universal coating; and (e) removing the removable three dimensionalstructure.

Alternatively, it is possible to design the negative three dimensionalstructure with two protruding nipples that can be removed (e.g., bygrinding), in order to create the input and output channels to theinterior of the structure. Next, the inside material is dissolved ormelted. The result is a structure entirely made out of the highlycorrosion resistant DLC, SiC, or other material. Further, packaging(e.g., coating, molding polymer, ceramic, metal deposition and/orplating) can be performed to give more structural stability.

The use of optical sensors previously described in the Summary of theInvention can facilitate the implementation of “smart” devices that canmonitor and control the concentration and amount of drug delivery.

An example of a smart device is a drug delivery microfluidic device 45as shown in FIG. 2. In one preferred embodiment, microfluidic device 45has at least one sensor 50. FIG. 2 shows a first sensor 50 and a secondsensor 53, however, any number of sensors 50 and 53 may be used asdesired. Sensors 50 and 53, which can be the same type of senor, canmonitor the physiological condition 60 of a local area of a patientbased on local chemistry, e.g., oxygen concentration, nitrous oxide,enzymes, or other optically detectable biological species. The readingsby sensor 50 at a first location 54 and the readings by sensor 53 at asecond location 55 can be converted to electrical signals andtransmitted to a smart electronics-actuator system 70 that can deliverthe required therapy to the patient based on the sensor reading. This isillustrated for a preferred embodiment in FIG. 2. Smartelectronics-actuator system 70 can comprise a microprocessor 80, a pump90, a drug reservoir 100, a reservoir effluent valve 121, and a drugdelivery catheter 110, defining a drug delivery passageway 119. Drugdelivery flow is shown by the arrows within drug delivery passageway119. Microprocessor 80, pump 90, and valve 121 can be powered by powersource 141. Because of the location of the sensors 50 and 53, device 45can monitor how the drug therapy is working at first location 54 as wellas at second location 55 by monitoring a bioelectric event or substanceto be detected 60 at those respective locations.

Drug reservoir 100 can contain a drug 101. Drug delivery catheter 110can have a diamond or diamond-like coating 120, and a sensor 111 thatcan monitor the amount, chemistry, and concentration of a drug 101pumped by pump 90 from reservoir 100 through the drug delivery catheter110. Diamond or diamond-like coating 120 can extend through pump 90,valve 121, and inside surface 100′ of drug reservoir 100, therebyproviding a protective barrier between the inside surfaces of thesemedical device components from drug 101. Sensor 111 shown in FIG. 2 isan electrochemical sensor. Sensor 111 can comprise a boron doped area112, and a sputtered metal piece 113. An electrical signal from drug101, after it is pumped by pump 90, can go through the boron doped area112 of diamond or diamond-like coating 120. Boron doped area 112 canalternatively be made into a photon detector, which can be made of anysuitable material, including but not limited to for e.g., asemiconductor, or silicon diode array. Thus, sensor 111 can “lookinside” catheter 110 to monitor drug 101 amount, chemistry andconcentration as drug 101 is being pumped through catheter 110. Further,sensor 111 can detect problems and electronically communicate thoseproblems to microprocessor 80, which can then electronically controlvalve 121 and/or change the pumping of drug 101 by pump 90 as may bedesired.

Further, this embodiment can enable in situ mixing of drug mixtures withpoor shelf life and thus extend the usefulness of such drug mixtures.For example, as shown in FIG. 2, reservoir 100 can include a firstpre-mix container 102 holding a first pre-mix drug 103, and a secondpremix container 104 holding a second pre-mix drug 105. First pre-mixcontainer 102 can have an effluent pre-mix valve 106, and second pre-mixcontainer 104 can have an effluent pre-mix valve 107. Pre-mix valves 106and 107 can be in electronic communication with microprocessor 80. Thus,microprocessor 80 can adjust the mixing of pre-mix drugs 103 and 105 asmay be desired based readings by sensor 111, as well as by sensor(s) 50.

Sensors 50 and 53 shown in FIG. 2, are electrochemical sensors. Sensors50 and 53 each comprises a boron doped area 51 of a diamond ordiamond-like film or coating 200, and a sputtered metal piece 220 incontact therewith. Sensors 50 and 53 can each detect the bioelectricevent or substance to be detected 60, such as a biological material, agas, or a mineral. The electrical signal from the bioelectric event orsubstance to be detected 60 can go through boron doped area 51 ofdiamond or diamond-like coating 200. Alternatively, boron doped area 51can be made into a photon detector, which can be made of any suitablematerial, including but limited to for e.g., a semiconductor, or silicondiode array.

The transmittance or reflectance of the bioelectric event or subtonic tobe detected 60 can be observed using a single or multiple wavelengthlight source 52. Devices focusing on oxygen requirements in blood havebeen described (see U.S. Pat. Nos. 3,690,769; 4,523,279, 4,750,495, and4,114,604, which are incorporated herein by reference). The sensorsdescribed in these devices use the same basic optical principle as thesensor(s) 50 of the present invention.

Alternatively, a sensor 130, similar to the sensors 111, 50 and 53 canbe located at distal end 140 of catheter 110 to monitor bioelectricevent or substance to be detected 60 at or near the discharge opening150 of catheter 110. More specifically, sensor 130 can have a borondoped area 131, and a sputtered metal piece 132, and be in electricalcommunication with microprocessor 80 via wire 133. An electrical signalfrom a bioelectric event can be detected and sent to the microprocessorfor analysis. The transmittance or reflectance of the bioelectric eventor substance to be detected 60 can be observed by sensor 130 adapted asan optical sensor using a single or multiple wavelength light source134.

Sensors 50, 53, 111 and 130 have been described as electrochemicalsensors. These sensors can be fabricated in a number or ways to providea boron or other type of doped areas on diamond or diamond like coating,and interconnect those doped areas to microprocessor. A fabricationmethod may include: 1) selective masking and 2) doping with boron as itis routinely done in the fabrication of semiconductors (see U.S. Pat.Nos. 4,961,958, and 4,676,847, which are incorporated herein byreference).

Those skilled in the art will recognize that the sensors can be acombination of any number and types of sensors in accordance with thepresent invention as may be desired. For example sensors 50, 53, 111,and 130 can be electrochemical and/or optical sensors.

While the device described and shown in FIG. 2 is a drug deliverydevice, the device can also provide electrical stimulation at electrodetip 145 at distal end 140 of catheter. Those skilled in the art willrecognize that an electrical stimulation wire 142, supplied withelectrical power from power source 141, can be contained within catheter110 in place of or in addition to drug delivery passageway 119, so as tobe able to provide and electrical stimulation at distal end 140. Thiselectrical stimulation can be controlled by microprocessor 80 based onsensor readings as previously described. The electrical field from thiselectrical stimulation can aid the delivery of the drug by a phenomenonknown as electrochemical migration. High voltage can be used toelectroporate tissue thus facilitate the delivery of drugs.

Those skilled in that art will recognize that the preferred embodimentsmay be altered or amended without departing from the true spirit andscope of the invention, as defined in the accompanying claims. Thus,while various alterations and permutations of the invention arepossible, the invention is to be limited only by the following claimsand equivalents.

I claim:
 1. An implantable medical device comprising: a medical devicecomponent, the medical device component having an outer surface and aninner surface, a universal coating applied to at least the outer surfaceor the inner surface of the medical device component, and a sensorplaced between the coating and the medical device component or withinthe coating, the sensor capable of measuring a bioelectric event orsubstance to be detected, the sensor electrically connected to amicroprocessor in the device, the microprocessor controlling drugdelivery by the medical device.
 2. The implantable medical device ofclaim 1 wherein the coating is made from materials selected from thegroup consisting of diamond, diamond-like, borosilicate glass, carbides,and nitrides.
 3. The implantable medical device of claim 1 wherein thesensor is an optical sensor, the device further having a light source toemit light to a substance to be monitored by the optical device.
 4. Theimplantable medical device of claim 1 wherein the sensor is anelectrochemical sensor.
 5. The implantable medical device of claim 1wherein the sensor is a boron doped area.
 6. The implantable medicaldevice of claim 5 wherein the boron doped area is in contact with asputtered metal piece.
 7. An implantable medical device comprising: amedical device component, the medical device component having an outersurface and an inner surface, a universal coating applied to at leastthe outer surface or the inner surface of the medical device component,and a sensor placed between the coating and the medical device componentor within the coating, the sensor capable of measuring a bioelectricevent or substance to be detected, the sensor electrically connected toa microprocessor in the device, the microprocessor controllingelectrical stimulation by the medical device.
 8. The medical device ofclaim 7 wherein the coating is made from materials selected from thegroup consisting of diamond, diamond-like, borosilicate glass, carbides,and nitrides.
 9. The medical device of claim 7 wherein the sensor is anoptical sensor, the device further having a light source to emit lightto a substance to be monitored by the optical sensor.
 10. The medicaldevice of claim 7 wherein the sensor is an electrochemical sensor. 11.The implantable medical device of claim 7 wherein the sensor is a borondoped area.
 12. The medical device of claim 11 wherein the boron dopedarea is in contact with a sputtered metal piece.